Is Pete Wentz’s Shirt An Ashlee Simpson Diss? [PHOTOS]

Just a day after Ashlee Simpson flaunted her affection for Vincent Piazza in New York City, Pete Wentz went out with a mystery brunette.

On Monday, July 11, the Fall Out Boy bassist was caught on camera taking a stroll with the female companion in Los Angeles. She’s probably just a friend.

PHOTOS: Pete Wentz’s Shirtless Beach Outing With Bronx

I’m curious about Pete’s choice of fashion. His t-shirt reads “The Not Fucking Around Crew.” Could that be in response to the rumors that started after Pete was spotted with ex-girlfriend Michelle Trachtenberg last week? Or are they in response to Ashlee flaunting her new love in public?

Sound off! Tell us what you think by tweeting us @socialitelife and share your thoughts by leaving a comment below.

UPDATE: I’m obviously not a Fall Out Boy fan, so I was totally oblivious of the the meaning behind the t-shirt. Thanks to our commentator enzymes (such interesting names you have) for setting me straight.